Muscle diseases, such as for example myopathies and rhabdomyeloses, are diseases of the muscles which can for example be triggered by the administration of statins.
Statins, which include the active substance atorvastatin, are medicinal substances which are 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG CoA reductase) inhibitors. HMG CoA in turn is an intermediate of human cholesterol synthesis, because of which statins are mainly used as cholesterol lowering agents in fat metabolism disorders. Here, through the inhibition of HMG CoA reductase, the statins effect a lipid lowering in the blood. Since HMG CoA is a substance involved in the biosynthesis of cholesterol, less cholesterol is formed in the body under the action of statins than without the administration of statins. Inter alia, examples of the statins include atorvastatin, cerivastatin, fluvastatin, lovastatin, pravastatin, rosuvastatin and simvastatin.
Although statins are generally regarded as useful drugs, there are problems in the therapy, namely firstly as regards the uncertainty in the prediction of the effect corresponding to a certain dose, and secondly in the risk of the development of undesired drug effects (also abbreviated herein as “UDE” and generally also described as side-effects).
All statins, including atorvastatin, can cause undesired drug effects, among which the most severe are the so-called toxic myopathies, wherein there are structural and functional changes in the skeletal musculature. The most severe form of toxic myopathy is rhabdomyelosis, which inter alia manifest themselves in complete laming of all four limbs and can often take a fatal course. Up to the year 2003, ca. 3350 cases of rhabdomyelosis triggered by lipid lowering agents had been described in the literature.
Also, the strength of action of the various statins at present obtainable on the market is different; thus for example fluvastatin exhibits a low myopathy incidence, but on the other hand exhibits one of the weakest lipid lowering actions even at the maximum dosage.
As further undesired drug effects during the use of statins such as atorvastatin, liver damage, a decline in memory performance and alertness, as well as increased aggressivity and increased irritability have been observed, as well as headache, nausea, anemia, nerve damage, hair loss, and the like.
Since not all patients who are subjected to treatment with statins, in particular atorvastatin, for lowering the cholesterol content develop undesired drug effects, and patients react differently to certain statins, in particular atorvastatin, and the dosages thereof, it would be desirable to be able to determine, in advance of statin therapy, in particular atorvastatin therapy, the predisposition of a patient to develop undesired drug effects or to react other than as desired to the therapy.